Self-releasing frictional window sash balance

ABSTRACT

A shoe having a tapered aperture between resilient side walls which include friction pads on their outer surfaces has a size and shape to fit within the jamb channel. The shoe is mounted to the edge rail of a movable window sash by means of a bracketretainer unit which movably retains a tapered resilient member within the tapered aperture of the shoe such that as the window is moved upward, the resilient tapered material moves relative to the tapered aperture in the shoe to minimize the force exerted by the shoe pads against the window jamb. When the window is stationary, however, the weight of the window causes the resilient tapered material to move relative to the side walls to forcibly engage them and push the associated pads against the sides of the jamb thereby holding the window in any desired raised position by the resulting frictional force between the pads and the sides of the jamb channel. The bracket-retainer can be adjusted to increase or decrease the frictional holding force as required in different installations, and the bracket is resiliently flexible to facilitate removal of the sash from its jamb.

United States Patent 1191 Teggelaar et al.

1 SELF-RELEASING FRICTIONAL WINDOW SASH BALANCE [75] Inventors: Claude Teggelaar; William T. De

Bruyn, both of Grand Rapids, Mich.

[73] Assignee: Wolverine Industries, Inc., Grand Rapids, Mich.

[221 Filed: Feb. 16, 1972 [2]] Appl. No.: 226,786

2,543,913 3/1951 Krouse..... 49/437 2,521,836 9/1950 Deal 16/193 2,673,113 3/1954 Gi0rdan0...-. 49/417 X 3,501,867 3/1970 Scott 49/451 X Primary Examiner-Kenneth Downey Attorney, Agent, or FirmPrice, Heneveld, l-luizenga & Cooper [111 3,788,006 1451 Jan. 29, 1974 57 ABSTRACT A shoe having a tapered aperture between resilient side walls which include friction pads on their outer surfaces has a size and shape to fit within the jarnb channel. The shoe is mounted to the edge rail of a movable window sash by means of a bracket-retainer unit which movably retains a tapered resilient member within the tapered aperture of the shoe such that as the window is moved upward, the resilient tapered material moves relative to the tapered aperture in the shoe to minimize the force exerted by the shoe pads against the window jamb. When the window is stationary, however, the'weight of the window causes the resilient tapered material to move relative to the side walls to forcibly engage them and push the associated pads against the sides of the jamb thereby holding the window in any desired raised position by the resulting frictional force between the pads and the sides of the jamb channel. The bracket-retainer can be adjusted to increase or decrease the frictional holding force as required in different installations, and the bracket is resiliently flexible to facilitate removal of the sash from its jamb.

16 Claims, 9 Drawing Figures PATENTED JAN 2 9 I974 SHEET 1 0F 2 FIG. 4

FIG. 9

SELF-RELEASING FRICTIONAL WINDOW SASII BALANCE BACKGROUND OF THE INVENTION The present invention relates to a sash balance or window positioner, and particularly to a self-releasing friction-operating device.

A very basic problem with single or double-hung windows designed to be raised and lowered by sliding within vertical jamb channels is that they tend to stick if the window sash is fitted too tightly against the corresponding window jamb. Conversely, if the window sash is too loosely fitted to the window jamb, the window will not remain in a raised position. Thus, frequently, this type of window either cannot be easily raised and lowered or it cannot reliably be positioned at a variety of stationary positions.

To overcome these basic problems, many different types of sash balances have been developed in the past which will allow the jambs to fit with only a very light sliding contact against the sash, or indeed with almost no frictional contact at all, with the balance operating to hold the window or sash in its raised position while simultaneously preventing sticking of the window against the jamb. Such balances include, for example, bias springs which aid in holding the window in a raised position and various pulley and counterweight or spring-loaded arrangements. With the advent of aluminum or like metal windows and casings, various frictional devices have been developed and employed to avoid use of the pully and bias-spring arrangements, which are costly and complex. However, such frictional devices have themselves proved to be costly and complex in many cases and, in addition, they have for the most part had one predominant shortcoming, i.e., the friction has been a constant factor existing when the sash is both raised or lowered. Thus, the friction must have such a magnitude as to exceed the weight of the window itself, in order to hold the latter stationary in any desired raised position. Consequently, to lower the window the frictional resistance can be overcome without undue difficulty since the weight of the window helps" or complements the downward force applied by the user, but raising the sash is another matter entirely, requiring the user to overcome a force exceeding the weight of the window, plus lifting the weight of the window itself. As may be readily appreciated, this has been a severe detriment to the use of such balance devices, often compelling the use of more complicated and more expensive devices which operate more easily. In addition to the complexity and therefore relatively high cost of known prior art devices using springs, weights, pulleys and the like the latter frequently require lubrication or other maintenance for proper operation, and operation of many such devices is marginal or prone to malfunction. Additionally, many of these devices require a different size or design for windows of different width and weight, therefore requiring the manufacturer to provide a variety of such devices for use with the various window types.

SUMMARY OF THE INVENTION window in place are automatically removed when the window is lifted, thereby requiring the user to lift only the weight of the window itself. Furthermore, the device is adapted to be used with any width of window and windows of a variety of weights. The device is easy to install by using existing screws in the metal window sash. It requires no lubrication and therefore is greaseless, clean to handle and requires no periodic maintenance. The device provides an adjustment such that it can be used with a variety of different weight windows and has visible calibration marks such that it can be preset to a desired holding friction for a given window. The balance or positioner of the invention can be easily installed or replaced in the field without requiring part or all of the window casing to be removed. It is relatively inexpensive and employs only a very few parts. Since only one moving part is used, the device has an extended useful life. The device operates very smoothly providing desirable window-lifting properties as well as holding properties combined with quiet operation.

Devices embodying the present invention include a shoe having resilient side walls with pads on the outer surfaces. The side walls are internally tapered or convergent to define an elongated wedge-shaped aperture therebetween. The shoe is fitted between the side walls or flanges of a window jamb channel and is coupled to the movable window sash by means of a mountingretaining unit which includes a resilient wedge that is fitted within the wedge-shaped aperture of the shoe and movable in relation therewith as the window sash is moved upwardly and downwardly. As the window is moved upwardly the resilient wedge moves to reduce or eliminate the spreading force against the inner surfaces of the side walls of the shoe, which then exerts only a very minimal or negligible friction force between the pads of the shoe and the sides of the jamb channel. When the window is released in a desired position of elevation, however, the resilient wedge moves downwardly relative to the wedge-shaped aperture in the shoe such that the resilient wedge forcibly engages the inner surfaces of the aperture side walls in the shoe to spread the side walls outwardly andforce the pads carried thereby against the sides of the jamb, thereby increasing the frictional contact between the shoe pads and the jamb and providing a frictional holding force for the window. 1

In an alternative embodiment, the shoe is formed from a pair of relatively flat members, each of which include a springable side tab as an integral part. The members include camming means therebetween such that as the window is moved upwardly, the side tabs provide a minimum contact force against the side walls of the jamb. When the window is moved in a downward direction, however, the camming means skew the rectangular members thereby increasing the frictional contact between the shoe and window jamb to hold the window in any desired raised position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary front elevational view of a window assembly employing a frictional window positioning device of the present invention on either side of the window sash;

FIG. 2 is an exploded enlarged perspective view of the frictional positioning device of the present invention showing a portion of the window sash and jamb channel;

FIG. 3 is a front elevational view of the resilient wedge member shown in FIG. 2;

FIG. 4 is a front elevational view of the frictional positioning device in its assembled form;

FIG. 5 is a partial side elevational view in cross section of the frictional positioning device in its installed position illustrating the manner in which it can be moved to facilitate removal of the window from the window jamb;

FIG. 6 is a side elevation in central cross section showing a different embodiment of the invention;

FIG. 7 is a sectional view taken along the plane VII VII in FIG. 6;

FIG. 8 is a detailed front elevational view of one portion of the embodiment shown in FIG. 7; and

FIG. 9 is a detailed front elevational view of another portion of the embodiment shown in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a doublehung type of window assembly 10 having an upper window pane l2 bordered by a sash including side rails 14 and 16 and a bottom rail 15. Window 10 further includes a lower window pane 20 which is bordered by a sash comprising a top rail 22 (shown fragmented to reveal the lower sash rail of the top window), side rails 24 and 26 and a bottom rail 28. The lower window includes a window positioner 40 mounted on each end of the top rail 22. The window positioner 40 is mounted to the rail 22 by means of screws 23 or other suitable fastening means. The positioners extend into the left and right window jamb channels 30 and 32 respectively, and provide a bidirectional, frictional force as described below, such that the lower window pane can be easily raised and yet will reliably maintain a raised position.

Referring now to FIG. 2, there is shown an exploded view of one of the identical window positioners 40, and of the top and side rails 22 and 26 respectively of the lower window pane 20, together with the window jamb channel 32. The window jamb channel 32 is generally a U-shaped extruded aluminum member having a pair of side walls 34 and 36 joined by an end wall 38. Each of the side walls 34 and 36 have an inner surface 35 and -37, respectively. The side rail 26 of the window sash likewise is manufactured from a U-shaped extruded aluminum member having side walls and 27 joined by an end wall 29. The end wall of the sash channel is somewhat narrower than the end wall 38 of the jamb channel 32, such that the sash rail 26 will fit within the jamb channel 32 with some clearance between the outside surfaces of the sash rail side walls 25 and 27 and the inner surfaces and 37 of the jamb channel side walls 34 and 36, respectively. Additionally, the width of the top and bottom rails 22 and 28 respectively of the sash for window pane 20 is less than the distance between the end walls of the left and right jamb channels 30 and 32. Thus, without additional window holding or positioning means, the window pane 20 and its associated sash fit relatively loosely within the jamb channels 30 and 32. The window positioning devices 40 shown in FIGS. 1 and 2, however, are mounted on each side of the window, on the ends of the top rail 22, so as to provide a smoothly operating window which will remain in any desired raised position.

The window positioning device 40 comprises a shoe 50, a retainer 60, a resilient wedge having side pieces 76 and 78 removably mounted thereto, a sash mounting bracket 80, a U clamp 90 and a fastener screw 95, as shown in FIG. 2. The shoe 50 is preferably made from a resilient plastic material such as nylon and comprises a pair of side walls 52 and 54 to which are secured (as by integral molding) a pair of pads 53 and 55, respectively. The side walls 52 and 54 include inner surfaces 52 and 54' and are joined by means of a top end wall 56 and a bottom end wall 58. A strip 51 of low friction type such as Teflon may be secured on each surface 52', 54. The top end wall 56 is somewhat wider than the bottom end wall 58 such that a downwardlyconverging tapered aperture 59 is formed between the inner surfaces of the walls 52, 54, 56, and 58. The angle formed thereby is approximately 10. The pads 53 and 55 have outer surfaces 43 and 45, respectively, which can be moved inwardly by resiliently flexing the walls 52 and 54 but which tend to return to their original shape by springing outwardly when the distorting force is released. A U-shaped bias spring 57 can be molded within the top wall 56 and side walls 52 and 54 to aid in providing outward spring force for pads 53 and 55. The spring 57 may comprise spring steel material, and may be of flat leaf spring stock. Also, a U-shaped spring of this nature can be placed inside the shoe 50 after molding, with the legs of the spring bearing outward aganist sides 52' and 54', and with the strips 51 carried on the legs of the spring.

The retainer 60 comprises a generally rectangulated body 62 having a threaded aperture 64 adapted to receive the fastening screw 95. The body 62 has a first forwardly-projecting rectangular portion 63 and a second somewhat wider mid-portion 65, as shown in FIG. 2. The second portion 65 of the body 62 has a rectangular aperture 66 extending transversely therethrough and adapted to receive the resilient wedge 70 and its associated side pieces 76 and 78. The body 62 of the retainer 60 has a rectangular flange or base plate portion 68 which is somewhat wider than the first and second portions 63 and 65, respectively, and is wider than the trapezoidal aperture 59 in the shoe 50. Like the shoe 50, the retainer 60 can be molded from nylon.

The wedge 70 shown in detail in FIG. 3 is manufactured from a stiffly resilient material such as a relatively hard synthetic rubber and has a pair of slots 72 and 74 in its sides 71 and 73, respectively, which are adapted to receive the raised portions 75 and 77 of the side pieces 76 and 78 respectively associated with the wedge 70 (FIG. 2). The trapezoidal-shaped wedge 70 further includes a top edge 79 and a bottom edge 79', the top edge being somewhat wider than the bottom edge as shown in FIG. 3, such that the sides 71 and 73 taper convergently downward from the top to the bottom of the wedge. The side pieces 76 and 78 are made from a relatively low frictional material such as a lubricous polymer of the type identified by the trademark Teflon, and serve to reduce the friction between the sides of wedge 70 and the inner surfaces 52' and 54' of sides 52 and 54 of shoe 50, as explained below.

The mounting bracket 80 (FIG. 4) is made from spring steel or other sheet material of like resilient characteristics and includes an elongated body 82 having a front face 83 and a rear face 81. A lip 84 is formed at the top of bracket 80, and below the lip 84 is an elongated rectangular aperture 86, with a pair of dimples (or, alternatively, holes) 87 formed in the body 82 on either side of aperture 86. The aperture 86 is sifficiently wide to allow insertion therethrough of the first portion 63 of the retainer 60, and sufficiently long such that the first portion 63 of the retainer 60 can be slid in a generally vertical direction within the aperture 86 to provide an adjustment for the positioning device 40 as explained below. The mounting bracket 80 further includes an angular bend 85 at a lower portion of the body 82 which is reinforced by an indent or emboss 88 formed in the body 82. A second aperture 89 is formed at the lower end of the bracket 80 and is adapted to receive the mounting screw 23 therethrough.

The U clamp 90 has an aperture 92 therethrough adapted to receive the fastening screw 95 and a series of calibration marks 93 in each of the legs or side walls 91 and 94 of the clamp.

The positioning device 40 is assembled by first positioning the side pieces 76 and 78 on either side of the wedge 70 and sliding the wedge and side pieces thereon together into the aperture 66 of the retainer 60. The combined retainer and wedge unit is then fitted within the aperture 59 of the shoe 50 such that the side pieces 76 and 78 associated with the wedge 70 are in alignment with and adjacent the inner side surfaces 52' and 54' of side walls 52 and 54 respectively of the shoe 50. The combined wedge and retainer unit has a height less than that of the aperture 59, and can therefore slide vertically within the latter.

The first rectangular portion 63 of body 62 of retainer 60 is extended forwardly through the mounting bracket aperture 86 and the U clamp 94 is positioned over the protruding first portion 63 such that the aperture 92 in the U clamp 94 is in alignment with the aperture 64 in the rectangular portion 63 of the retainer body 62, holding the retainer to the bracket 80 with the shoe 50 held between the rear face 81 of bracket 80 and the flange 68 of the retainer 60. The device 40 is then attached to the top rail 22 of the window sash by means of the fastening screw 23 which extends through the aperture 89 in the mounting bracket 80 and then into a mounting hole 31 in the top rail 22 of the sash.

As seen in FIG. 4, the pads 53 and 55 of the shoe 50 protrude beyond the edges of the mounting bracket 80. Also, the U clamp 94 is somewhat wider than the aperture 86 in the mounting bracket 80 such that the edges 97 and 98 (FIG. 2) of the clamp 94 will contact the face 83 of the mounting bracket 80, thereby securely holding the retainer 60 to the mounting bracket 80 with the shoe 50 movably disposed therebetween. Referring to FIG. 2, the depth of the second portion 65 of the rectangular body 62 of the retainer 60 is at least slightly greater than the depth of the shoe 50, such that with the front surfaces of the portion 65 drawn against the rear face 81 of the mounting bracket 80, the shoe 50 is allowed to freely slide in a vertical direction between the flange 68 of the retainer 60 and the rear face 81 of the mounting bracket.

Installation of a window sash unit having a pair of the positioning devices 40 attached to either end of the top rail 22 is accomplished as shown in FIG. 5 by shifting the sash to the left as far as possible and resiliently flexing the mounting bracket 80 inwardly (i.e., towards the center of the window) such that the shoe 50 and retainer 60 will clear the sides 34 and 32 of each jamb channel, and then removing the window pane and associated sash from the jamb channels.

position of the The operation of the positioning device to provide a bi-frictional sliding and holding control for the window can best be understood by referring to FIGS. 2, 3 and 4. As noted above, the shoe 50 is slidably mounted to the bracket 80 by the retainer 60. The pads 53 and 55 of the shoe 50 will normally always contact the jamb channel with at least a light frictional engagement, and to this extent always tend to hold the shoe in a fixed position in the jamb channel 32, while the retainer 60 and wedge therein move upwardly, in the direction indicated by the arrows 100 (FIG. 2). Initially, the shoe 50 remains in place in the jamb channel. As the retainer 60 slides in the upward direction within the aperture 59 of shoe 50, the retainer eventually contacts the upper end 56 of shoe 50, at which time the latter is then pushed upward to follow the bracket 80. The wedge 70 is shaped such that with the side pieces 76 and 78 in place on the wedge, the side pieces will loosely contact the inner sides 52' and 54' of the shoe 50 when the retainer 60 is in abutment with the top 56 of the shoe, as the window is being raised. Thus, during the raising of the window, the frictional force between the pads 53 and 55 of the shoe 50 and the surfaces 35 and 37 of the sides 34 and 36 of the jamb channel 32 is at a minimum and constant, and the shoe 50 will easily slide upwardly in the jamb channel 32 as the window is raised, with the degree of required force being essentially only that necessary to lift the weight of the window.

Once the window is raised, however, the weight of the window causes the window to initially drop slightly downwardly while the shoe 50 remains in place, since the resiliency of the side walls of shoe 50 and the bias spring 57 provides a sufficient outward force to hold the shoe 50 stationary in the channel 32 when no other forces are applied, the retainer unit 60 and wedge 70 are linked directly to the window, and thus move downwardly within the aperture 59 of the shoe 50, such that the wedge 70 and its side pieces 76 and 78 spread, or at least apply pressure to) the sides 52 and 54 of the shoe outwardly, causing the pads 53 and 55 to forcibly engage the sides of the jamb channel 32 with sufficient friction to cause not only the shoe but the entire window assembly to remain fixed in the jamb channel. That is, the window pane 20 and the sash associated therewith is held in the desired raised position by the action of the wedge 70 (and its side pieces) against the sides of the shoe defining the downwardly convergent aperture 59, since the wedge is securely held by the retainer 60, which is in turn attached to the mounting bracket 80 affixed to the window.

The positioning device 40 can be adjusted by loosening the fastening screw 95 and sliding the retainer 60 relative to the slotted aperture 86 in the mounting bracket 80. As seen in FIG. 2 the lip 84 on the mounting bracket 80 limits the upward travel of the shoe 50 such that as the vertical position of the retainer 60 relative to the bracket 80 is adjusted, the maximum downward travel of the wedge relative to the shoe 50 is limited by the spacing between the lip 84 and the secured retainer 60 on the bracket 80. If for example the U-clamp and retainer 60 are fixed as shown in FIG. 4 near the bottom of the slot 86 in the bracket 80, a relatively large frictional holding force for heavy windows can be obtained. This results because the wedge 70 can move downward a considerable distance within the aperture 59 of shoe 50. If however the retainer 60 and U-clamp 90 were adjusted toward the top of slot 86 in bracket 80, the relative motion between the shoe and wedge would be limited to a relatively short distance and the wedge could not move downwardly within slot 59 as great a distance as before. Thus, a lesser frictional holding force results, for smaller and lighter-weight windows than in the earlier example. The window is lowered in a conventional manner applying a downward force to the sash. Since it is only necessary that sufficient frictional holding forces be selected (by making the adjustments mentioned above) to overcome the weight of the window, only a slight additional downward force is necessary to close the window.

In making adjustments of the positioning device of the foregoing character, the calibration marks 93 on the sides 91 and 94 of the U-clamp provide a visual scale which is read in relationship to the dimples or holes 87 on the bracket 80, which also serve to center the U-clamp with respect to the aperture 86. Of course, the position of the U-clamp at any adjustment accurately reflects the relative position of the retainer 60 and the wedge 70 carried thereby with respect to the allowable travel of the shoe 50. Consequently, the calibration marks are an accurate indication of the frictional holding force which the device will produce at the different positions of allowable adjustment.

FIGS. 7 through 9 show an alternative embodiment of the present invention in which a window positioning device comprises a mounting bracket molded of nylon or other suitable material. The bracket 120 may have a generally triangular channel shape, as shown in FIG. 6, with a central slot 122 formed therein to allow a fastening bolt 123 to pass through an aperture 124 in the bottom leg 126 of the bracket, thereby securing the bracket to a top rail 130 of a window sash. The bracket 120 has a width as illustrated in FIG. 7 which allows it to fit within the side walls 134 and 136 of a jamb channel 138 having an end wall 139. The bracket 120 further includes a relatively flat outer face 125 (at the right side as seen in FIG. 6) over which extends a protruding upper portion 127 having a threaded aperture 218 therein for receiving an adjustment screw 129. Bracket 120 further includes a centrally disposed laterally projecting post 121 which extends outwardly from surface 125, as shown in FIGS. 6 and 7, which can be integrally molded with the bracket 120 or, as shown, separately inserted post.

The positioning device 110 further includes first and second relatively flat friction engagement members 140 and 150, shown in detail in FIGS. 8 and 9 respectively. Members 140 and 150 have body portions and 155 respectively with longitudinal axes A and B respectively. Elongated apertures 146 and 156 respectively are formed centrally of the bodies 145 and 155 respectively and, each such aperture is skewed slightly laterally in relation to the axes A and B in the manner shown in FIGS. 8 and 9. The member further includes a second slotted aperture 157 which has a longitudinal axis generally perpendicular to the axis B. The member 140 has a post 147 integrally molded therewith which is adapted to slidably engage aperture .157 of member 150 when the members 140 and 150 are coupled together as shown in FIGS. 6 and 7.

Each of the members 140 and 150 has a resilient side wall formed by slots 141 and 151 in the respective members which form tabs 142 and 152, respectively, which at least in part are in the nature of the resilient side walls and pads of the shoe described previously. The slots 141 and 151 are sufficiently wide to allow resilient compression of the tabs 142 and 152 inwardly toward the body 145 and155, respectively, of members 140 and 150. When the members 140 and 150 are layed or stacked in juxtaposition as shown in FIGS. 6 and 7, they form a shoe with movable side walls. The skewed elongated apertures 146 and 156 are adapted to fit in slidable engagement with the post 121 of mounting bracket 120, as shown in FIGS. 6 and 7.

In operation, the shoe formed by the two members 140 and 150 is mounted between the sides 134 and 136 of the jamb channel 138 and retained on the pin 121 of the mounting bracket 120 by means of a force fitted washer 143 or the like. The members 140 and 150 can slide vertically in relation to bracket 1 10 along the longitudinal axes A and B respectively and are guided by pin 121 and the sides 134 and 136 of the jamb channel 138.

When the window is being raised, members 140 and 150 tend to initially remain in place by virtue of the contact of resilient tabs 142 and 152 against the sides 136 and 134 respectively of the window jamb 138. When the pin 121, which moves with the raising window, contacts the top edge of the slots 146 and 156 however, the members 140 and 150 are raised with the window. As the window is released at the desired raised position, it tends to drop slightly causing pin 121 to move downwardly along the slots 146 and 156. The tabs 142 and 152 are sufficiently compressed just prior to the movement of pin 121 downwardly such that they hold the members 140 and 150 in place between the sides 134 and 136 of the jamb channel 138. As the pin 121 moves downwardly, it will be seen by referring to FIGS. 7, 8 and 9 that this tends to draw the longitudinal slots 146 and 156 into alignment at the bottom where the slots are skewed a maximum distance from axes A and B. Since the slots 146 and 156 are skewed in relation to the axes A and B of members 140 and 150, the top portion of the two members will be spread outwardly apart as member 140 rotates relative to member 150 about the pin 147 of member 140 in aperture 157 of member. In this manner, therefore, the holding force exerted by the sides of the members 140 and 150 against the sides 134 and 136 of the window jamb 138 is increased an amount sufficient to cause the raised window to remain in position. An adjustment screw 129 acts to limit the maximum upward travel of members 140 and 150 and, therefore, the relative motion between the pin 121 and slots 146 and 156 and adjustment of this screw will thus vary the maximum force of the shoe provided by members 140 and 150 acting against the sides of the jamb channel, to provide a holding force which fits the requirements of a particular weight window.

It is entirely conceivable that upon examining the foregoing disclosure, those skilled in the art may devise embodiments of the concept involved which differ somewhat from the embodiment shown and described herein, or may make various changes in structural details to the present embodiment. Consequently, all such changed embodiments or variations in structure which utilize the concepts of the invention and clearly incorporate the spirit thereof are to be considered as within the scope of the claims appended herebelow, unless these claims by their language specifically state other- WISC.

We claim:

1. A self-releasing frictional window sash balance or positioning device adapted to be mounted on a vertically movable window sash and fitted between side walls of a corresponding window jamb channel, said device comprising: a shoe having a pair of side portions for contacting said sides of said jamb channel, at least one of said side portions comprising a resiliently flexible integral part of said shoe defining a vertically tapered space between itself and another surface of said shoe and being movable toward and away from a side of the channel; means for coupling said shoe to a window sash such that said side portions are positioned adjacent said sides of the jamb channel; and means for mounting only on said window sash and for forcing said side portions of said shoe against said sides of the jamb channel in response to movement of the sash only in a first direction, to thereby increase the frictional force between said shoe and the jamb channel only when the window sash is moved in said first direction, said increased frictional force having a magnitude sufficient to hold said window in a stationary position relative to said jamb following said sash movement in said first direction, said forcing means comprising a wedging member having angularly disposed side portions; means for coupling said member to said mounting means with said member disposed within said tapered space and against said flexible part of said shoe such that said member is movable in relation to said tapered space and such that said member forcibly contacts said flexible side part of said shoe when said window sash is moved in said first direction thereby applying an increasing outward force pressing said flexible side part of said shoe outwardly against the side of the jamb channel.

2. The device of claim 1, including a pair of said resiliently flexible integral shoe parts, said vertically tapered space disposed generally therebetween.

3. A self-releasing frictional window sash balance or positioning device adapted to be mounted on a vertically movable window sash and fitted between side walls of a corresponding window jamb channel, said device comprising:

a shoe having a pair of side wall portions for contacting said sides of said jamb channel, said side wall portions comprising resiliently flexible integral side walls of said shoe defining a vertically tapered space therebetween and being movable toward and away from said sides of the channel;

means for coupling said shoe to a window sash such that said side wall portions are positioned adjacent said sides of the jamb channel; and

means for mounting only on said window sash and for forcing said side wall portions of said shoe against said sides of the jamb channel in response to movement of the sash only in a first direction, to thereby increase the frictional force between said shoe and the jamb channel only when the window sash is moved in said first direction, said increased frictional force having a magnitude sufficient to hold said window in a stationary position relative to said jamb following said sash movement in said first direction, said forcing means comprising a tapered member, means for coupling said member to said mounting means with said member disposed within said tapered space and between said side wall portions of said shoe such that said member is movable in relation to said tapered space and such that said tapered member forcibly contacts said side wall portions of said shoe when said window sash is moved in said first direction thereby applying an increasing outward force pressing said side wall portions of said shoe against the sides of the jamb channel.

4. The device as defined in claim 1 wherein said shoe comprises first and second members each having sides with at least one resilient edge portion, each of said members further including a skewed elongated slot means formed therein, a post comprising at least a part of said mounting and forcing means and extending through said elongated slot means in said shoe, and means coupling said members such that as the movable window sash is moved in said first direction, said post acts against said slot means to move said members relative to one another in a direction to force said sides thereof against the sides of the jamb channel.

5. The device of claim 1, wherein said shoe has resilient side walls joined to end walls so as to define a wedge-shaped aperture therebetween, pads coupled to said side walls on the sides thereof opposite from said wedge-shaped aperture and adapted to be fitted within a window jamb, a wedge and a retainer adapted to hold said wedge within said wedge-shaped aperture in said shoe, and bracket means coupled to said retainer and adapted to be coupled to a window sash such that as the window sash is moved in a first direction, said wedge moves relative to said shoe such that said side walls of said shoe member are pressed outwardly thereby causing said pads to forceably engage the sides of the jamb channel.

6. The device as defined in claim 5 wherein said wedge includes tapered sides having a shape complementary to that of said wedge-shaped aperture, said wedge being mounted in said aperture such that said tapered wedge sides are disposed approximately parallel to said sides of said shoe. 7

7. The device as defined in claim 6 wherein said wedge forceably contacts the sides of said shoe to press said side walls outwardly only when the window sash is moved in a downward direction.

8. A self-releasing frictional window positioning device comprising:

a shoe having resilient side walls joined to end walls so as to define a wedge-shaped aperture therebetween, pads coupled to said side walls on the sides thereof opposite from said wedge-shaped aperture and adapted to be fitted within a window jamb, a wedge and a retainer adapted to hold said wedge within said wedge-shaped aperture in said shoe, said wedge including tapered sides having a shape complementary to that of said wedge-shaped aperture, said wedge being mounted in said aperture such that said tapered wedge sides are disposed ap proximately parallel to said sides of said shoe and forcibly contact the sides of said shoe to press said side walls outwardly only when the window sash is moved in a downward direction;

bracket means coupled to said retainer and adapted to be coupled to a window sash such that as the window sash is moved in a first direction, said wedge moves relative to said shoe such that said side walls of said shoe member are pressed outwardly thereby causing said pads to forcibly engage the sides of the jamb channel; and

friction-reducing means coupled between said sides of said shoe and said sides of said wedge to facilitate relative sliding motion between said shoe and said wedge as the window sash is moved.

9. A window positioning device adapted to be mounted to a sash of a movable window and extend into a jamb channel associated therewith to provide a relatively low frictional force when the window is raised and provide an increased holding frictional force once the window is in a desired raised position, said device comprising:

a shoe having trapezoidal frame portions with nonparallel sides at least one of which is resiliently movable;

a wedge shaped to fit within the trapezoidal frame portions of said shoe; and

means for mounting said wedge in slidable engagement with said trapezoidal frame portions, said mounting means comprising a mounting bracket having an elongated slot therein and a retainer having a portion thereof extending through said elongated slot of said bracket for holding said wedge thereto such that said shoe is held between the sides of a jamb channel and said wedge is coupled to a sash of a movable window, and such that as said window is moved in an upward direction said wedge moves toward the divergent part of the trapezoidal frame portions of said shoe and as said movable window is moved in a downward direction said wedge moves toward the convergent part of said frame portions to forcibly engage said nonparallel sides thereof and force said resiliently movable side outwardly against the side of the jamb channel.

10. The apparatus as defined in claim 9 and further including means for limiting the relative motion between said shoe and said wedge to provide a predetermined, maximum frictional holding force'between said shoe and the window jamb channel for each motion limit selected.

11. The window positioning device as defined in claim 10 where said limiting means comprises a lip on said mounting bracket adapted to contact said shoe in one extreme position of said shoe and means for adjustably securing said retainer at any of a plurality of positions along said rectangular aperture of said mounting bracket thereby limiting the other extreme position of said shoe.

12. A window positioning device adapted to be mounted to a movable window sash and including a shoe with portions disposed within a jamb channel associated with such window sash to provide a relatively low frictional force between the window sash and the jamb channel as the window is raised, and an increased holding frictional force between the window sash and the jamb channel once the window is in a desired raised position, said device comprising a mounting bracket adapted to be secured to a rail of the window sash, a post extending from said mounting bracket in a direction generally parallel to the top rail of the window sash, a first member having a pair of spaced sides extending in the same general direction and an elongated slot skewed relative to the longitudinal axis of said member, a second member with similar spaced sides and having an elongated slot skewed with respect to its longitudinal axis in a direction opposite to the longitudinal slot of said first member, said first and second members mounted to said mounting bracket such that said post extends through said skewed elongated slots in said first and second members, and means coupling said first and second members such that as said members move relative to said post, said first and second members slidably rotate with respect to each other.

13. The window positioning device as defined in claim 12 and further including adjusting means for limiting the relative motion of said first and second members with respect to said post.

14. A window positioning device to be mounted between a movable window sash and a window jamb associated with said window sash to provide a relatively low frictional force between the sash and jamb as the window is raised and an increased holding frictional force once the window is in a desired raised position, said device comprising:

a shoe having side walls, said shoe side walls comprising resiliently flexible trapezoidal frame portions; jamb-contacting pads carried by said side walls and movable with respect to said jamb;

a mounting bracket for coupling said shoe between the window sash and the associated window jamb; and

means for moving said pads into holding frictional engagement against the window jamb only when the sash is moved in a first direction, said means for moving said pads comprising:

a tapered member; and

means for coupling said member to said mounting bracket to position said member adjacent said trapezoidal frame portions of said shoe and in slidable engagement with the latter such that as the window sash is moved in a first direction, said tapered member forcibly contacts said trapezoidal portions thereby applying an increased outward force thereto and resiliently flexing such portions outwardly toward the jamb.

15. The window positioning device as defined in claim 14 wherein said mounting bracket has a configu ration such that said resilient side walls of said shoe are positioned between oppositely-disposed sides of the associated window jamb.

16. A window positioning device to be mounted between a movable window sash and a window jamb associated with said window sash to provide a relatively low frictional force between the sash and jamb as the window is raised and an increased holding frictional force once the window is in a desired raised position, said device comprising: a shoe having side walls; jambcontacting pads carried by said side walls and movable with respect to said jamb; a mounting bracket for coupling said shoe between the window sash and the associated window jamb; means for moving said pads into holding frictional engagement against the window jamb only when the sash is moved in a first direction; and means cooperating with said shoe and said moving means for adjustably selecting the maximum frictional holding force, said shoe comprising first and second generally flat and rectangular members each having a resiliently flexible portion along at least one edge, said members disposed in layered relation, and camming means coupling said members together such that as the window sash is moved in said first direction said members move relative to one another and to said mounting bracket to force their said flexible edge portions into frictional engagement between portions of the asso' ciated window jamb.

* i i t i 

1. A self-releasing frictional window sash balance or positioning device adapted to be mounted on a vertically movable window sash and fitted between side walls of a corresponding window jamb channel, said device comprising: a shoe having a pair of side portions for contacting said sides of said jamb channel, at least one of said side portions comprising a resiliently flexible integral part of said shoe defining a vertically tapered space between itself and another surface of said shoe and being movable toward and away from a side of the channel; means for coupling said shoe to a window sash such that said side portions are positioned adjacent said sides of the jamb channel; and means for mounting only on said window sash and for forcing said side portions of said shoe against said sides of the jamb channel in response to movement of the sash only in a first direction, to thereby increase the frictional force between said shoe and the jamb channel only when the window sash is moved in said first direction, said increased frictional force having a magnitude sufficient to hold said window in a stationary position relative to said jamb following said sash movement in said first direction, said forcing means comprising a wedging member having angularly disposed side portions; means for coupling said member to said mounting means with said member disposed within said tapered space and against said flexible part of said shoe such that said member is movable in relation to said tapered space and such that said member forcibly contacts said flexible side part of said shoe when said window sash is moved in said first direction thereby applying an increasing outward force pressing said flexible side part of said shoe outwardly against the side of the jamb channel.
 2. The device of claim 1, including a pair of said resiliently flexible integral shoe parts, said vertically tapered space disposed generally therebetween.
 3. A self-releasing frictional window sash balance or positioning device adapted to be mounted on a vertically movable window sash and fitted between side walls of a corresponding window jamb channel, said device comprising: a shoe having a pair of side wall portions for contacting said sides of said jamb channel, said side wall portions comprising resiliently flexible integral side walls of said shoe defining a vertically tapered space therebetween and being movable toward and away from said sides of the channel; means for coupling said shoe to a window sash such that said side wall portions are positioned adjacent said sides of the jamb channel; and means for mounting only on said window sash and for forcing said side wall portions of said shoe against said sides of the jamb channel in response to movement of the sash only in a first direction, to thereby increase the frictional force between said shoe and the jamb channel only when the window sash is moved in said first direction, said increased frictional force having a magnitude sufficient to hold said window in a stationary position relative to said jamb following said sash movement in said first direction, said forcing means comprising a tapered member, means for coupling said member to said mounting means with said member disposed within said tapered space and between said side wall portions of said shoe such that said member is movable in relation to said tapered space and such that said tapered member forcibly contacts said side wall portions of said shoe when said window sash is moved in said first direction thereby applying an increasing outward force pressing said side wall portions of said shoe against the sides of the jamb channel.
 4. The device as defined in claim 1 wherein said shoe comprises first and second members each having sides with at least one resilient edge portion, each of said members further including a skewed elongated slot means formed therein, a post comprising at least a part of said mounting and forcing means and extending through said elongated slot means in said shoe, and means coupling said members such that as the movable window sash is moved in said first direction, said post acts against said slot means to move said members relative to one another in a direction to force said sides thereof against the sides of the jamb channel.
 5. The device of claim 1, wherein said shoe has resilient side walls joined to end walls so as to define a wedge-shaped aperture therebetween, pads coupled to said side walls on the sides thereof opposite from said wedge-shaped aperture and adapted to be fitted within a window jamb, a wedge and a retainer adapted to hold said wedge within said wedge-shaped aperture in said shoe, and bracket means coupled to said retainer and adapted to be coupled to a window sash such that as the window sash is moved in a first direction, said wedge moves relative to said shoe such that said side walls of said shoe member are pressed outwardly thereby causing said pads to forceably engage the sides of the jamb channel.
 6. The device as defined in claim 5 wherein said wedge includes tapered sides having a shape complementary to that of said wedge-shaped aperture, said wedge being mounted in said aperture such that said tapered wedge sides are disposed approximately parallel to said sides of said shoe.
 7. The device as defined in claim 6 wherein said wedge forceably contacts the sides of said shoe to press said side walls outwardly only when the window sash is moved in a downward direction.
 8. A self-releasing frictional window positioning device comprising: a shoe having resilient side walls joined to end walls so as to define a wedge-shaped aperture therebetween, pads coupled to said side walls on the sides thereof opposite from said wedge-shaped aperture and adapted to be fitted within a window jamb, a wedge and a retainer adapted to hold said wedge within said wedge-shaped aperture in said shoe, said wedge including tapered sides having a shape complementary to that of said wedge-shaped aperture, said wedge being mounted in said aperture such that said tapered wedge sides are disposed approximately parallel to said sides of said shoe and forcibly contact the sides of said shoe to press said side walls outwardly only when the window sash is moved in a downward direction; bracket means coupled to said retainer and adapted to be coupled to a window sash such that as the window sash is moved in a first direction, said wedge moves relative to said shoe such tHat said side walls of said shoe member are pressed outwardly thereby causing said pads to forcibly engage the sides of the jamb channel; and friction-reducing means coupled between said sides of said shoe and said sides of said wedge to facilitate relative sliding motion between said shoe and said wedge as the window sash is moved.
 9. A window positioning device adapted to be mounted to a sash of a movable window and extend into a jamb channel associated therewith to provide a relatively low frictional force when the window is raised and provide an increased holding frictional force once the window is in a desired raised position, said device comprising: a shoe having trapezoidal frame portions with non-parallel sides at least one of which is resiliently movable; a wedge shaped to fit within the trapezoidal frame portions of said shoe; and means for mounting said wedge in slidable engagement with said trapezoidal frame portions, said mounting means comprising a mounting bracket having an elongated slot therein and a retainer having a portion thereof extending through said elongated slot of said bracket for holding said wedge thereto such that said shoe is held between the sides of a jamb channel and said wedge is coupled to a sash of a movable window, and such that as said window is moved in an upward direction said wedge moves toward the divergent part of the trapezoidal frame portions of said shoe and as said movable window is moved in a downward direction said wedge moves toward the convergent part of said frame portions to forcibly engage said non-parallel sides thereof and force said resiliently movable side outwardly against the side of the jamb channel.
 10. The apparatus as defined in claim 9 and further including means for limiting the relative motion between said shoe and said wedge to provide a predetermined, maximum frictional holding force between said shoe and the window jamb channel for each motion limit selected.
 11. The window positioning device as defined in claim 10 where said limiting means comprises a lip on said mounting bracket adapted to contact said shoe in one extreme position of said shoe and means for adjustably securing said retainer at any of a plurality of positions along said rectangular aperture of said mounting bracket thereby limiting the other extreme position of said shoe.
 12. A window positioning device adapted to be mounted to a movable window sash and including a shoe with portions disposed within a jamb channel associated with such window sash to provide a relatively low frictional force between the window sash and the jamb channel as the window is raised, and an increased holding frictional force between the window sash and the jamb channel once the window is in a desired raised position, said device comprising a mounting bracket adapted to be secured to a rail of the window sash, a post extending from said mounting bracket in a direction generally parallel to the top rail of the window sash, a first member having a pair of spaced sides extending in the same general direction and an elongated slot skewed relative to the longitudinal axis of said member, a second member with similar spaced sides and having an elongated slot skewed with respect to its longitudinal axis in a direction opposite to the longitudinal slot of said first member, said first and second members mounted to said mounting bracket such that said post extends through said skewed elongated slots in said first and second members, and means coupling said first and second members such that as said members move relative to said post, said first and second members slidably rotate with respect to each other.
 13. The window positioning device as defined in claim 12 and further including adjusting means for limiting the relative motion of said first and second members with respect to said post.
 14. A window positioning device to be mounted between a movable window sash and a window jamb associated with said window sash to provide a relatively low frictional force between the sash and jamb as the window is raised and an increased holding frictional force once the window is in a desired raised position, said device comprising: a shoe having side walls, said shoe side walls comprising resiliently flexible trapezoidal frame portions; jamb-contacting pads carried by said side walls and movable with respect to said jamb; a mounting bracket for coupling said shoe between the window sash and the associated window jamb; and means for moving said pads into holding frictional engagement against the window jamb only when the sash is moved in a first direction, said means for moving said pads comprising: a tapered member; and means for coupling said member to said mounting bracket to position said member adjacent said trapezoidal frame portions of said shoe and in slidable engagement with the latter such that as the window sash is moved in a first direction, said tapered member forcibly contacts said trapezoidal portions thereby applying an increased outward force thereto and resiliently flexing such portions outwardly toward the jamb.
 15. The window positioning device as defined in claim 14 wherein said mounting bracket has a configuration such that said resilient side walls of said shoe are positioned between oppositely-disposed sides of the associated window jamb.
 16. A window positioning device to be mounted between a movable window sash and a window jamb associated with said window sash to provide a relatively low frictional force between the sash and jamb as the window is raised and an increased holding frictional force once the window is in a desired raised position, said device comprising: a shoe having side walls; jamb-contacting pads carried by said side walls and movable with respect to said jamb; a mounting bracket for coupling said shoe between the window sash and the associated window jamb; means for moving said pads into holding frictional engagement against the window jamb only when the sash is moved in a first direction; and means cooperating with said shoe and said moving means for adjustably selecting the maximum frictional holding force, said shoe comprising first and second generally flat and rectangular members each having a resiliently flexible portion along at least one edge, said members disposed in layered relation, and camming means coupling said members together such that as the window sash is moved in said first direction said members move relative to one another and to said mounting bracket to force their said flexible edge portions into frictional engagement between portions of the associated window jamb. 